S5 derailleur hanger

[warthog1]

Keep an eye on your derailleur hanger S5 owners.
Mine broke recently, luckily at low speed.
Derailleur dropped down into the spokes scratching the drive side seat stay on the way through and locking the rear wheel.
Mechanic at the LBS where I bought the bike has seen acouple of others break also. The top part of the hanger is fairly thin and has a retaining screw through it weakening it further.
Probably good practice to check it out visually after any knocks and every time the back wheel is out.

[Dr_Mutley]

Very good idea...
I replaced mine with a wheels mfg hanger as I noticed the cervelo issue hanger was quite soft, and I was sick of truing it every month or so to keep my gear changing smooth. The wheels replacement is much stiffer, the trade off obviously being yourself likely to damage your rear drop out in a crash if there's impact to the derailleur.....

[warthog1]

I knew wheels mfg did derailleur hangers but had no idea if they did an S5 one.
Thanks Dr Mutley, I'll have to chase one up too. If that hanger had broken at speed the result could have been very ugly so I'd rather take my chances with a stronger one too.

[Dr_Mutley]

Just a thought... Why did the hanger fail? Was it just a spontaneous failure? If so it would seem uncommon.....

I know I have posted this somewhere, but I can't remember where (may have been on the cervelo forum), but I'm very suspicious that a lot of the cervelo hanger and drop out failures isn't due to the hangers, but to loosening of the hanger screws. I noticed my S5 screws had a bad habit of vibrating loose, and this was the initial reason my RD was loosing its tune, resulting in poor shifting. I tightened the hanger screws several times, and ended up loctiting them as they continually came loose. I'm suspicious that the common R3 rear hanger / dropout breakages was probably in part due to this. So I guess the bottom line is, keep an eye on the RD hanger screws, and to be doubly sure, loctite them when u install them. As your now quite aware, when your in 39/25, there isn't much room for error between the RD and the spokes!

[warthog1]

I have crashed it. The hanger didn't need straightening afterwards though the derailleur is lightly scuffed at the pivot point the b screw adjusts.
The hanger is pretty thin and is weakened by the retaining screw, but the crash no doubt didn't help.
The mechanic mentioned he had seen other S5 hangers fail where it broke either side of the retaining screw hole.
I was still one or two gears away from the top of the cassette when it broke. The derailleur ended up in the spokes after it fell off.
I'll keep an eye on those screws too thanks, though the hanger is also clamped by the QR I reckon.
Ordered a wheels mfg one from arts cyclery.

[warthog1]

Apparently there are a couple of derailleur hanger designs for S5's. Mine is the later one. Hanger 163;



My hanger broke at the second screw hole, the hole after 163 in the photo.

According to the wheels mfg site some early S5's use hanger 156;

[Dr_Mutley]

The 156 design is the hanger all the 2011 R3 had problems with, mainly snapping off the rear dropout...

[warthog1]

I can see why you'd need to watch the retaining screws with that one Doc. Doesn't look like that would be too well clamped by the QR

[Dr_Mutley]

Yeah... A mate brought over his R3 last night and there is a horizontal fatigue line through the hanger combined with loose screws... (I should've taken a pic if it)

I warned him not to ride it until the replacement wheels mfg hanger arrives... Or it will end up looking like this common R3 scenario -

[warthog1]

Ouch